Edge-Gated Injection Molding Apparatus

ABSTRACT

An edge-gated injection molding apparatus is disclosed having an injection manifold assembly for distributing a melt stream of moldable material to a plurality of mold cavities aligned on opposing sides of the injection manifold assembly. The injection manifold assembly includes a plurality of melt outlets with each melt outlet being in fluid communication with a respective mold cavity, and a plurality of biasing components disposed along a centerline of the injection manifold assembly. A nozzle seal is disposed between each injection manifold assembly melt outlet and its corresponding mold cavity, with an upstream end of the nozzle seal being slidably disposed against its respective melt outlet. Each biasing component is disposed between a pair of melt outlets and corresponding nozzle seals for biasing the melt outlets and nozzle seals outward from the centerline of the injection manifold assembly toward their respective mold cavities and applying a preload thereto.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/803,859 filed Mar. 14, 2013, which claims the benefit under 35 U.S.C.§119(e) of U.S. Appl. No. 61/612,149 filed Mar. 16, 2012. Each of theafore-mentioned applications is incorporated by reference herein in itsentirety.

FIELD OF THE INVENTION

The present invention relates to an injection molding apparatus, andmore particularly, to an edge-gated injection molding apparatus.

BACKGROUND OF THE INVENTION

Edge-gating applications have been developed that use an injectionmanifold that is in fluid communication with either a radial array ofmold gates and associated mold cavities or a linear array of mold gatesand associated mold cavities. When providing a melt stream to a moldgate, a nozzle tip for delivering the melt stream to the mold gate isideally centered in the gate orifice under operating conditions toensure consistent part quality. When providing the melt stream to aradial array of mold gates in an edge-gated application, injectionmanifolds known in the art tend to be cylindrical or puck-shaped, whichresults in thermal expansion of the injection manifold under operatingconditions being directed primarily radially outward from a center ofthe injection manifold toward each nozzle tip and associated mold gatesuch that alignment between the nozzle tip and mold gate issubstantially constant under both hot and cold conditions. Accordingly,each nozzle tip may have an upstream end thereof held within a sidesurface of the cylindrical or puck-shaped injection manifold and adownstream end thereof held within a cavity plate or cavity insert thatforms the mold gate without thermal expansion adversely affectingoperation thereof.

When providing the melt stream to a linear array of mold gates in anedge-gated application, injection manifolds known in the art tend to berectangular in shape with a row of nozzle tips secured within each ofthe opposing sides of the injection manifold that are aligned with acorresponding row of mold gates. In order to assure alignment betweeneach nozzle tip and its respective mold gate under operating conditions,in the cold condition a pitch spacing between adjacent nozzle tips/meltoutlets of a rectangular injection manifold is less than a spacingbetween their corresponding mold gates, which may be formed within acavity plate or a respective cavity insert. However with thermalexpansion of a rectangular injection manifold occurring in both lateraland longitudinal directions, each nozzle tip may experience a differentamount of movement towards and/or transverse to its mold gate dependingon the linear position of the nozzle tip along its respective side ofthe injection manifold. If such a linear injection manifold feeds onlyfour mold cavities having a relatively close pitch spacing, that is twoper side, the injection manifold will be relatively small and heatexpansion will be minimal such that each nozzle tip may have an upstreamend thereof held within a side surface of the rectangular injectionmanifold and a downstream end thereof held within a cavity plate orcavity insert that forms the mold gate without thermal expansionadversely affecting operation thereof. Conversely, if a linear injectionmanifold feeds a larger number of mold cavities having a relativelyclose pitch spacing or a smaller number of mold cavities having arelatively large pitch spacing, such as eight mold cavities with fourper side, for example, there may be as much as 0.2 mm-0.3 mmmisalignment between the outermost nozzle tips/melt outlets of theinjection manifold, and the corresponding mold gates in a coldcondition. During the thermal expansion of heated components that occursduring injection molding operations, a misalignment of this magnitudemay cause severe stress on a nozzle tip that is being held, as isconventional, by both the injection manifold and cavity plate/cavityinsert, and may in some instances cause a downstream end of the nozzletip to contact a wall of the cavity plate/cavity insert that surroundsthe mold gate, which may damage the nozzle tip and or result in a moldedpart of poor quality.

Embodiments disclosed herein are directed towards edge-gated injectionmolding applications for providing a melt stream to a linear array ofmold gates and associated mold cavities that solve at least theaforementioned problem associated with current linear array edge-gatingsolutions. In addition, embodiments hereof are directed to simplifyingnozzle tip replacement in edge-gating applications that does not requirecomplete disassembly of the mold and/or to relatively easily takingout-of-service an individual edge-gated mold cavity.

BRIEF SUMMARY OF THE INVENTION

Embodiments hereof are directed to an edge-gated injection moldingapparatus having an injection manifold assembly for distributing a meltstream of moldable material to a plurality of mold cavities aligned onopposing sides of the injection manifold assembly. The injectionmanifold assembly includes a plurality of melt outlets and a pluralityof biasing components that are securable along a centerline of theinjection manifold assembly so that each biasing component is disposedbetween an opposing pair of melt outlets. Each biasing component biasesthe opposing pair of melt outlets outward from the centerline of theinjection manifold assembly toward a respective mold cavity associatedwith each melt outlet. A plurality of nozzle seals are in fluidcommunication with the plurality of melt outlets of the injectionmanifold assembly for receiving the melt stream therefrom and deliveringthe melt stream to the plurality of mold cavities. An upstream end ofeach nozzle seal is slidably disposed against a respective melt outletof the injection manifold assembly and a downstream end of each nozzleseal is slidably received within a bore of a cavity plate or cavityinsert that surrounds a mold gate of a respective mold cavity associatedwith the respective melt outlet, which assures alignment between eachedge-gated nozzle seal and its respective mold gate under both hot andcold conditions.

The sliding relationship between the upstream end of each nozzle sealand its respective melt outlet of the injection manifold assembly, whilethe downstream end of the nozzle seal is securely held relative to themold gate, permits misalignment between a melt inlet of the nozzle sealand its respective injection manifold assembly melt outlet in the coldcondition without causing stress on the nozzle seal. Moreover when theedge-gated injection molding apparatus is brought to an operatingtemperature, the sliding relationship permits alignment between the meltinlet of the nozzle seal and its respective melt outlet to occur duringthermal expansion of the injection manifold assembly, which may occur inboth lateral and longitudinal directions depending on the linearposition of the nozzle seal along the injection manifold assembly. Inaddition, the outward biasing of each opposing pair of melt outlets byits respective biasing component applies a preload to the nozzle sealsassociated therewith such that an operator may more conveniently applyany required preload from the parting line P_(L) of the mold.

BRIEF DESCRIPTION OF DRAWINGS

The foregoing and other features and advantages of the invention will beapparent from the following description of embodiments thereof asillustrated in the accompanying drawings. The accompanying drawings,which are incorporated herein and form a part of the specification,further serve to explain the principles of the invention and to enable aperson skilled in the pertinent art to make and use the invention. Thedrawings are not to scale.

FIG. 1 is a perspective view of an edge-gated injection moldingapparatus in accordance with an embodiment hereof.

FIG. 1A is a bottom view of a portion of the edge-gated injectionmolding apparatus of FIG. 1 with the injection manifold assembly shownin section.

FIG. 2 is a perspective view of an injection manifold assembly inaccordance with an embodiment hereof.

FIG. 2A is an enlarged sectional view of the injection manifold assemblyof FIG. 2 as taken along line A-A of FIG. 2, with the injection manifoldshown installed within the injection molding apparatus of FIGS. 1 and 3.

FIG. 2B is a perspective view of a downstream end of a cavity insert inaccordance with an embodiment hereof.

FIG. 3 depicts a sectional view of the edge-gated injection moldingapparatus of FIG. 1 as taken along line A-A of FIG. 1.

FIG. 3A depicts an enlarged view of an area A of FIG. 3.

FIG. 4 depicts the disassembly of a portion of the injection moldingapparatus shown in FIG. 2A in accordance with an embodiment hereof.

FIG. 5 depicts the portion of the injection molding apparatus shown inFIG. 4 reassembled to include a dummy diverter block in accordance withan embodiment hereof.

FIG. 6 is a sectional view of an injection manifold assembly inaccordance with another embodiment hereof that shares features with theinjection manifold assembly of FIG. 2.

FIG. 7 is a perspective view of an injection manifold assembly inaccordance with another embodiment hereof.

FIGS. 8 and 9 are perspective views of an injection manifold assembly inaccordance with another embodiment hereof.

FIG. 8A is a cross-sectional view of the injection manifold assemblyshown in FIGS. 8 and 9 taken along line A-A of FIG. 8.

FIG. 8B is a sectional view of the injection manifold assembly shown inFIGS. 8 and 9 taken along line B-B of FIG. 8.

FIG. 9A is a sectional view of the injection manifold assembly shown inFIGS. 8 and 9 taken along line A-A of FIG. 9.

FIGS. 10A and 10B are sectional views of an injection manifold assemblyin accordance with another embodiment hereof.

DETAILED DESCRIPTION OF THE INVENTION

Specific embodiments of the present invention are now described withreference to the figures, wherein like reference numbers indicateidentical or functionally similar elements. The following detaileddescription is merely exemplary in nature and is not intended to limitthe invention or the application and uses of the invention. In thefollowing description, “downstream” is used with reference to thedirection of mold material flow from an injection unit of an injectionmolding machine to a mold cavity of a mold of an injection moldingsystem, and also with reference to the order of components or featuresthereof through which the mold material flows from the injection unit tothe mold cavity, whereas “upstream” is used with reference to theopposite direction. Although the description of embodiments hereof is inthe context of a hot runner injection molding system, the invention mayalso be used in other molding applications where it is deemed useful,nonlimiting examples of which include molding of thermoset resins suchas liquid silicone rubber or the like. Furthermore, there is nointention to be bound by any expressed or implied theory presented inthe preceding technical field, background, brief summary or thefollowing detailed description.

FIG. 1 is a perspective view of an edge-gated injection moldingapparatus 100 in accordance with an embodiment hereof, with FIG. 2 beinga perspective view of an injection manifold assembly 102 in accordancewith an embodiment hereof removed from injection molding apparatus 100.It would be understood by one of ordinary skill in the art thatinjection molding apparatus 100 constitutes a hot half of a moldingsystem that is designed to mate with a cold half and cavity inserts 104thereof in an injection molding machine (not shown). It also would beunderstood by one of ordinary skill in the art that in use injectionmolding apparatus 100 is housed within various mold plates, such as, forexample, a back plate 312, a manifold plate 314, a cooled mold plate 316and a cavity plate 318 as shown with reference to FIG. 3, which depictsa sectional view of apparatus 100 taken along line A-A of FIG. 1assembled for use.

With reference to FIGS. 1 and 3, edge-gated injection molding apparatus100 includes a heated inlet or sprue 105, a hot runner injection moldingmanifold 106 and two hot runner injection molding nozzles 108 fordirecting a melt stream of moldable material under pressure from aninjection molding machine nozzle (not shown) to an injection manifoldassembly 102 from which the melt stream is delivered to a plurality ofcavity inserts 104, as explained in more detail below. Sprue 105includes a heater 175, manifold 106 includes a heater 176, each nozzle108 includes a heater 178 and each injection manifold assembly 102includes a heater 172, which are provided for keeping the melt stream ofmoldable material at a proper processing temperature. Exemplary heatersfor use in embodiments hereof may include a wire element heater embeddedwithin or simply wrapped around the hot runner component, such asheaters 172, 175, 176, 178, or a band or cartridge heater wheresuitable. Sprue 105 is partially disposed within back plate 312 andincludes an inlet melt channel 325 for directing the melt streamreceived from the machine nozzle to a manifold melt channel 326 ofmanifold 106 that in turns divides the melt stream for distribution to arespective nozzle melt channel 328 of each injection molding nozzle 108.Each nozzle 108 directs the melt stream to a melt channel 332 ofinjection manifold assembly 102, as explained in more detail below. Aswould be understood by one of ordinary skill in the art, manifold 106 islocated within back plate 312 and cooled manifold plate 314 surroundedby an insulative air gap, wherein an axial position of manifold 106within the air gap relative to back plate 312 and manifold plate 314 ismaintained during operation by a locating ring 107 and various pressuredisks 109. Pressure disks 109 also aid in establishing a seal betweenmanifold 106 and each nozzle 108 to prevent melt leakage at theinterface between the respective manifold and nozzle melt channels 326,328 during operation. A person of ordinary skill in the art wouldunderstand that there are various ways to axially fix manifold 106within injection molding system without departing from the scope of thepresent invention.

Each nozzle 108 extends within a corresponding opening 330 defined bymanifold plate 314, mold plate 316 and an alignment insert 194 withincavity insert plate 318 a. Opening 330 is sized to provide an insulativeair gap between the heated nozzle 108 and the aforementioned cooledmanifold, mold and cavity insert plates 314, 316, 318 a. With referenceto FIG. 3A that depicts an enlarged view of an area A of FIG. 3, adownstream end 338 of each nozzle 108 is configured to be coupled to arespective injection manifold assembly 102 via a telescopic connector380 to permit relative sliding movement therebetween, so as toaccommodate axial thermal expansion along longitudinal axis L_(A). Anexemplary arrangement for telescopic connector 380 is represented inFIG. 3A, in which an upstream connector component 384 and a downstreamconnector component 386 are shown. Upstream connector component 384attached to nozzle downstream end 338 slides against alignment insert194 to align nozzle 108 with injection manifold assembly 102. Upstreamconnector component 384 is attached to nozzle downstream end 338 anddownstream connector component 386 is attached within an upstream end203 (also referred to herein as a melt inlet 203) of injection manifoldassembly 102 so as to be slidable relative to each other by way of asliding interface 388. While configurable in a variety of ways, slidinginterface 388 is shown as upstream connector component 384 providing astepped bore 383 in which a corresponding stepped extension 385 ofdownstream connector component 386 is slidingly received. In anembodiment, downstream end 338 of nozzle 108 is provided with a threadedbore 387 to receive a complimentary threaded portion of upstreamconnector component 384. Similarly, upstream end or melt inlet 203 ofinjection manifold assembly 102 is provided with a threaded bore 389 toreceive a complimentary threaded portion of downstream connectorcomponent 386. As such, nozzle 108 and injection manifold assembly 102are coupled via telescopic connector 380, whereby nozzle melt channel328 is in fluid communication with injection manifold melt channel 332.As such, telescopic connector 380 defines a linking melt channel 382 topermit the aforementioned fluid communication between melt channels 328,332 of nozzle 108 and injection manifold assembly 102. In an embodiment(not shown), upstream connector component 384 may be integrally formedwith nozzle downstream end 338 and downstream connector component 386may be integrally formed with upstream end 203 of injection manifoldassembly 102. In a further embodiment (also not shown), nozzle 108 maybe fixedly connected to injection manifold assembly 102, and atelescopic connector is used between an upstream end of nozzle 108 andmanifold 106.

FIG. 2 is a perspective view of injection manifold assembly 102 removedfrom injection molding apparatus 100 and FIG. 2A is an enlargedsectional view of injection manifold assembly 102 taken along line A-Aof FIG. 2, wherein the injection manifold assembly is depicted asinstalled within a portion of injection molding apparatus 100 as shownin FIG. 3. In the embodiment shown in FIG. 2, injection manifoldassembly 102 has a substantially brick or cuboid shaped injectionmanifold 260 that defines an upstream surface 211, a downstream surface213, opposing side surfaces 215, 215′ and opposing end surfaces 217,217′. A set of spacers 109 a shown on upstream surface 211 of injectionmanifold assembly 102 and are configured to mate within bores oropenings (not shown) within cavity insert plate 318 a to assure properpositioning and to create a standoff support with minimal heat loss.Spacers 109 a will counteract forces from one or more fasteners, such ascap screws 233, when injection manifold assembly 102 is installed asdiscussed further below.

FIG. 1A is a bottom view of a portion of edge-gated injection moldingapparatus 100 of FIG. 1 with injection manifold assembly 102 shown insection depicting a plurality of nozzle seals 244 in fluid communicationwith a plurality or cavity inserts 104 that are aligned along opposingside surfaces 215, 215′ of injection manifold assembly 102. Accordingly,injection manifold assembly 102 provides a melt stream to a linear arrayof mold cavities, each of which is partially defined by a respectivecavity insert 104. Injection manifold 260 has a continuous groove 201formed within its upstream and downstream surfaces 211, 213 and opposingside surfaces 215, 215′ for receiving a heating element 210 of heater172. With reference to FIGS. 2 and 3, a plurality of L-shaped couplersor clamps 231 and associated cap screws 233 are used to secure injectionmanifold assembly 102, and more particularly injection manifold 260, tocavity insert plate 318 a. The attachment of injection manifold 260 tocavity insert plate 318 a by L-shaped couplers 231 ensures that theinjection manifold 260 is held in place against the injection pressureforce at the inlet of connector component 386 in embodiments that use atelescopic connector to accommodate axial thermal expansion, such as theshown in the embodiment of FIG. 3. In addition, cap screws 233 andL-shaped couplers 231 are accessible from a parting line P_(L) ofedge-gated injection molding apparatus 102 upon removal of a cover plate318 b, such that the entire injection manifold assembly 102 may beremoved from the parting line P_(L) of the mold.

In another embodiment, an injection manifold 260 may be made of asufficient width and length such that longitudinal bores may be madetherein for receiving cap screws 233 there through to secure injectionmanifold 260 to a respective cavity insert plate 318 a, in whichcomplementary threaded holes for receiving a respective cap screw 233would be provided. In another embodiment, an injection manifold 260 maybe of a sufficient width and length so as to include threaded borestherein that align with through holes in a respective cavity insertplate 318 a through which cap screws 233 may extend to couple theinjection manifold 260 to the respective cavity insert plate 318 a.

Injection manifold 260 includes melt inlet 203 in upstream surface 211that is in fluid communication with melt channel 332 formed therein forreceiving a melt stream of moldable material, as described above, anddistributing the melt stream via a plurality of melt outlets 229 indownstream surface 213 to a plurality of diverter blocks 220. Eachdiverter block 220 includes a melt inlet 223 and a melt outlet 227 witha melt channel 221 extending therebetween. In the embodiment shown inFIGS. 2 and 2A, each diverter block 220 is individually coupled todownstream surface 213 of injection manifold 260 by cap screws 219 to bepositioned such that each diverter block melt inlet 223 is aligned witha respective melt outlet 229 in injection manifold bottom surface 213and such that a flat outside or exterior side surface 215 a of eachdiverter block 220, which includes a respective diverter block meltoutlet 227, is substantially parallel to a respective side surface 215,215′ of injection manifold 260. In the embodiment shown in FIG. 2A,diverter block melt channel 221 includes a substantially 90° bend fordirecting the melt stream received through diverter block melt inlet 223in an upstream surface thereof to diverter block melt outlet 227 inoutside or exterior side surface 215 a thereof.

A nozzle seal 244 is disposed against the melt outlet 227 of eachdiverter block 220 for receiving the melt stream therefrom. In theembodiment shown in FIGS. 2 and 2A, nozzle seal 244 includes a nozzletip 240 that is slidably received within a corresponding bore of a gateseal 242 such that the two pieces are substantially coaxial. Inembodiments hereof, nozzle tip 240 may be formed from a thermallyconductive material, such as beryllium copper or other copper alloy, andgate seal 242 may be formed from a less thermally conductive material,such H13 steel or titanium. A downstream end of gate seal 242 includesan outer circumferential face seal surface 245 that contacts and sealsagainst a first sealing surface 246 of cavity insert 104 and an innercircumferential, primary seal surface 247 that contacts and sealsagainst a second sealing surface 248 of cavity insert 104. Withreference to FIG. 2B, which is a perspective view of a downstream end ofcavity insert 104, second sealing surface 248 is located within acounter bore 248 a that surrounds a mold gate 222 of cavity insert 104.An upstream surface 241 of nozzle tip 240 and an upstream surface 243 ofits corresponding gate seal 242 are slidably disposed against arespective outside or exterior side surface 215 a of diverter block 220and are otherwise not directly attached or secured thereto. In anembodiment in the cold condition, upstream surface 241 of nozzle tip 240may extend or project from upstream surface 243 of gate seal 242 toconcentrate sealing forces at a mating diverter block melt outlet 227and nozzle tip melt inlet 241 a.

In another embodiment (not shown), nozzle seal 244 may be used in astraight-gated, as opposed to edge-gated, injection molding applicationwith outer circumferential face seal surface 245 contacting and sealingagainst a planar surface of a mold cavity plate or the like thatsurrounds a counter bore that defines a mold gate through a downstreamend thereof. Inner circumferential, primary seal surface 247 of nozzleseal 244 in this straight-gated injection molding application willcontact and seal against a second sealing surface 248 located within thecounter bore. An upstream surface 241 of nozzle tip 240 and an upstreamsurface 243 of its corresponding gate seal 242 will be slidably disposedagainst a respective downstream surface of an injection manifold to bein fluid communication with a melt outlet therein, but otherwise wouldremain unattached or unsecured thereto.

A series of biasing or wedge components 224 are coupled alongsubstantially a centerline C_(L) of downstream surface 213 of injectionmanifold 260 by respective cap screws 219 a such that each wedgecomponent 224 is disposed between a pair of diverter blocks 220. Withreference to FIG. 4, which shows a diverter block 220 and a wedgecomponent 224 disassembled from an injection manifold 260, wedgecomponent 224 has a trapezoidal cross-section with opposing side contactsurfaces 249 a, 249 b of wedge component 224 being angled toward eachother as each surface extends from a base surface 249 c to an apicalsurface 249 d, wherein a width of base surface 249 c is greater than awidth of apical surface 249 d. Each wedge component 224 defines alongitudinal bore 249 e for receiving a respective cap screw 219 a therethrough. In an embodiment, longitudinal bore 249 e may be threaded toreceive a complementary threaded tool, such as a larger sized sockethead cap screw, to assist in the removal of the wedge component 224. Aswell, the longitudinal bores (not shown) of each diverter block 220 forreceiving cap screws 219 may be threaded for the same purpose.

Each diverter block 220 includes an inside or interior side surface 215b that is angled to abut against a corresponding side contact surface249 a, 249 b of wedge component 224. With this configuration nozzleseals 244, diverter blocks 220, and wedge components 224 may beassembled and disassembled from a parting line P_(L) of the mold uponremoval of cover plate 318 b. Additionally, the torqueing of screw 219 awithin wedge component 224 biases an opposing pair of diverter blocks220 and associated nozzle seals 244 outward from centerline C_(L) of theinjection manifold assembly 102 toward their respective mold cavitiesthereby applying a preload to each of the nozzle seals 244 to helpprevent leakage at the interface between each diverter block 220 andinjection manifold 260 and at the interface between each diverter block220 and its associated nozzle seal 244 under operating conditions.Moreover, this configuration permits an operator to more convenientlyapply the preload from the parting line P_(L) of the mold after theremainder of injection molding apparatus 100 is already assembled. In anembodiment, the injection molding system may be brought to an operatingtemperature and thereafter a preload may be applied, as discussed above,to prevent scoring between upstream surfaces 241, 243 of nozzle tip 240and gate seal 242, respectively and outside or exterior side surface 215a of diverter block 220 that otherwise may have occurred if the preloadwere applied prior to heating-up the system.

Under operating conditions when injection manifold assembly 102undergoes thermal expansion, a respective angled inside or interior sidesurfaces 215 b of each diverter block 220 will bear against acorresponding side contact surface 249 a, 249 b of wedge component 224to assure that thermal expansion of diverter blocks 220 occurs in thedirection of the aforementioned interfaces. In embodiments hereof,accessibility of wedge component 224 from the parting line P_(L) of themold permits a sealing force between sealing interfaces of each diverterblock to be adjusted from parting line P_(L) and thereby prevent anexcessive load on the components of the system, for instance, if a lowpressure application is used.

The engagement between primary seal surface 247 of gate seal 242 andsecond sealing surface 248 of cavity insert 104, as described above,assures axial alignment of nozzle tip 240 with mold gate 222 in a coldcondition, and together with the function of wedge component 224 duringthermal expansion of injection manifold assembly 102, as described inthe preceding paragraph, assures axial alignment of nozzle tip 240 withmold gate 222 under operating conditions. Conversely components 240, 242of nozzle seal 244 and diverter block 220 may experience somemisalignment between diverter block melt outlet 227 and a melt inlet 241a of nozzle tip 240 in a cold condition. However as injection moldingapparatus 100 is heated to an operating temperature, the upstreamsurfaces 241, 243 of nozzle tip 240 and gate seal 242, respectively, areslidable along outside or exterior side or surface 215 a of diverterblock 220 during thermal expansion of the components to substantiallyeliminate any misalignment between diverter block melt outlet 227 andnozzle tip melt inlet 241 a under operating conditions. Accordingly whenused in linearly arranged edge-gated molding applications in accordancewith embodiments hereof, the slidable interface between melt inlets ofnozzle seals and melt outlets of the diverter blocks of the injectionmanifold assemblies permits thermal expansion of the injection manifoldassemblies with respect to the nozzle seals in both longitudinal andtransverse directions without damaging the nozzle seals or adverselyaffecting alignment between the nozzle seals and their respective moldcavities. Embodiments hereof may be used for high-cavity linearlyarranged edge-gated molding applications without worrying about thermalexpansion values, pitch distance, and/or the number of cavities ascurrently may be achieved in high-cavity straight-gated moldingapplications.

As noted above, FIG. 4 depicts a diverter block 220 and a wedgecomponent 224 disassembled from an injection manifold 260, whichprovides access from the parting line P_(L) of the mold upon removal ofcover plate 318 b to an associated nozzle seal 244 for assembly anddisassembly. In an embodiment shown in FIG. 5, injection manifoldassembly 102 is shown reassembled to include a dummy diverter block 220a that does not include a melt channel and is installed to selectivelyshut-down the mold cavity associated therewith. Dummy diverter block 220a has all other features of diverter block 220 so as to provide apreload at the interface between dummy diverter block 220 a andinjection manifold 260 as well as the paired diverter block 220 andnozzle seal 244 when wedge component 224 is secured to injectionmanifold 260 as previously discussed above.

FIG. 6 is a sectional view of an injection manifold assembly 602 inaccordance with another embodiment hereof that shares features with theinjection manifold assembly of FIG. 2. The embodiment of FIG. 6 may beused with all features described with reference to other embodimentshereof and only features that differ from those already described willbe detailed herein. Injection manifold assembly 602 has a substantiallybrick or cuboid shaped injection manifold 660 that defines an upstreamsurface 611, a downstream surface 613, opposing side surfaces 615, 615′and opposing end surfaces (not shown). Injection manifold 660 has acontinuous groove 601 formed in the upstream, downstream and opposingside surfaces thereof for receiving heating element 210 as similarlydescribed above.

Injection manifold 660 includes melt channel 632 formed therein forreceiving a melt stream of moldable material, as described above, anddistributing the melt stream via a plurality of melt outlets 629 indownstream surface 613 to a plurality of diverter blocks 620. Eachdiverter block 620 includes a melt inlet 623 and a melt outlet 627 witha melt channel 621 extending therebetween and is individually coupled toinjection manifold downstream surface 613 by one or more cap screws suchthat each diverter block melt inlet 623 is aligned with a respectiveinjection manifold melt outlet 629. Dowels 635 are shown extendingbetween corresponding bores in injection manifold downstream surface 613and the upstream surface of diverter block 620 to aid in aligning meltoutlet 629 and melt inlet 623 during assembly as well as to maintainalignment therebetween during thermal expansion that occurs as thesystem is brought to an operating temperature. Dowels may be used forthis purpose in each of the embodiments described herein that utilizediverter blocks.

An outside surface 615 a of each diverter block 620, which includes thediverter block melt outlet 627, is formed to be at an acute anglerelative to a centerline C_(L) of injection manifold assembly 602 suchthat each outside or exterior surface 615 a is angled relative to arespective side surface 615, 615′ of injection manifold 660. In theembodiment shown in FIG. 6, diverter block melt channel 621 includes abend having greater than a 90° angle for directing the melt streambetween diverter block melt inlet 623 in an upstream surface of diverterblock 620 and diverter block melt outlet 627 in angled outside surface615 a thereof.

A first sealing surface 646 of cavity insert 604 is also formed to be atan acute angle relative to the centerline C_(L) of injection manifoldassembly 602 so as to be substantially parallel with outside or exteriorsurface 615 a of diverter block 620. First sealing surface 646 surroundsa counter bore of cavity insert 604 that ends in mold gate 622 anddefines a second sealing surface 648 of cavity insert 604. As similarlydescribed with reference to the embodiment of FIG. 2A, an upstreamsurface of nozzle seal 244 that includes nozzle tip melt inlet 241 a isslidingly disposed against outside surface 615 a of diverter block 620to be in fluid communication with diverter block melt outlet 627 and adownstream end of nozzle seal 244 is axially aligned with mold gate 622.More particularly, face seal surface 245 of gate seal 242 contacts andseals against first sealing surface 646 of cavity insert 604 and primaryseal surface 247 of gate seal 242 contacts and seals against secondsealing surface 648 of cavity insert 604 such that a longitudinal axisI_(A) of nozzle tip 240 is held at an injection angle Θ relative to atransverse axis T_(A) of cavity insert 604 that passes through mold gate622 under both hot and cold conditions. In an embodiment, injectionangle Θ is between 10° and 20°, however it should be understood thatangle Θ can be between 0° and 90°. Nozzle seal 244 so positionedintroduces the melt stream of moldable material toward a base of a coreinsert (not shown) of the mold cavity, which is beneficial to preventcore displacement in certain molding applications.

A series of wedge components 224 are coupled to downstream surface 613of injection manifold 660 in a similar manner as shown and describedwith reference to the embodiment of FIG. 2A. Each diverter block 620includes an inside surface 615 b that is angled to abut against acorresponding side contact surface 249 a, 249 b of wedge component 224.This configuration permits nozzle seals 244, diverter blocks 620, andwedge components 224 to be assembled and disassembled from parting lineP_(L) of the mold. Additionally, an operator may torque a cap screw 219a within wedge component 224 to bias an opposing pair of diverter blocks620 and associated nozzle seals 244 outward from a centerline C_(L) ofinjection manifold assembly 602 toward their respective mold cavitiesthereby applying a preload to each of the nozzle seals 244 that preventsleakage at the interface between each diverter block 620 and injectionmanifold 660 and at the interface between each diverter block 620 andits associated nozzle seal 644 under operating conditions. Moreoverafter the remainder of the injection molding apparatus is assembled,this configuration permits an operator to apply any required preloadfrom the parting line P_(L) of the mold. In an embodiment, the injectionmolding system may be brought to an operating temperature and thereaftera preload may be applied, as discussed above, to prevent scoring thatotherwise may have occurred if the preload were applied prior toheating-up the system.

As in the previous embodiment, components 240, 242 of nozzle seal 244and diverter block 620 may experience some misalignment between diverterblock melt outlet 627 and a melt inlet 241 a of nozzle tip 240 in a coldcondition. However as injection manifold assembly 602 is heated to anoperating temperature, the upstream surfaces 241, 243 of nozzle tip 240and gate seal 242, respectively, are slidable along outside surface 615a of diverter block 620 during thermal expansion of the components tosubstantially eliminate any misalignment between diverter block meltoutlet 627 and nozzle tip melt inlet 241 a under operating conditions.Accordingly when used in linearly arranged edge-gated moldingapplications in accordance with embodiments hereof, the slidableinterface between melt inlets 241 a of nozzle seals 244 and melt outlets627 of diverter blocks 620 of injection manifold assembly 602 permitsthermal expansion of the injection manifold assembly to occur withrespect to the nozzle seals in both longitudinal and transversedirections without damaging the nozzle seals or adversely affectingalignment between the nozzle seals and their respective mold cavities.

FIG. 7 is a perspective view of an edge-gated injection manifoldassembly 702 in accordance with another embodiment hereof that sharesfeatures with edge-gated injection manifold assembly 102 of FIG. 2. Theembodiment of FIG. 7 may be used with all features described withreference to other embodiments hereof and only features that differ fromthose already described will be detailed herein. Injection manifoldassembly 702 includes a T-shaped injection manifold 760 that has acontinuous groove 701 formed within its upstream surface 711 andopposing side surfaces 715, 715′ for receiving a heating element 710 ofa heater 772. Injection manifold 760 may be used in place of injectionmolding nozzle 108, telescopic connector 380 and injection manifold 260in injection molding apparatus 100, which was described with referenceto FIGS. 1 and 3. With injection manifold assembly 702 so installed ininjection molding apparatus 100, a melt inlet at an upstream end 703 ofinjection manifold 760 is configured for transferring a melt stream ofmoldable material received from hot runner manifold 106 through a seriesof melt channels of injection manifold 760 (not shown) to a plurality ofmelt outlets in a downstream surface 713 of injection manifold 760. Eachmelt outlet of injection manifold 760 is in fluid communication with arespective diverter block 220 for delivering a portion of the meltstream thereto.

As similarly described with reference to the embodiments above, eachdiverter block 220 is secured to downstream surface 713 of injectionmanifold 760 via cap screws 219 and has a melt outlet 227 that is influid communication with a nozzle seal 244 for injecting the melt streaminto a mold cavity of a respective cavity insert 104 during a moldingcycle. Nozzle seal 244 has an upstream end that is slidably disposedagainst a surface that surrounds melt outlet 227 of diverter block 220and has a downstream end that is secured within a corresponding borethat surrounds a mold gate of the respective mold cavity associatedtherewith, as described with reference to the previous embodiments. Inthis manner, the downstream end of the gate seal of nozzle seal 244seals on an outer circumferential surface within the counter boresurrounding it respective mold gate and assures axial alignment ofnozzle tip 240 with the mold gate under both cold and hot conditions. Asin the previous embodiment, the slidable interface between nozzle seal244 and diverter block 220 permits some misalignment between a meltinlet 241 a of nozzle tip 240 and its respective melt outlet 227 in acold condition. However as edge-gated injection manifold assembly 702 isheated to an operating temperature, the upstream surfaces 241, 243 ofnozzle tip 240 and gate seal 242, respectively, are slidable along thesurface of diverter block 220 during thermal expansion of the componentsto substantially eliminate any misalignment between nozzle tip meltinlet 241 a and its respective diverter block melt outlet 227 underoperating conditions. Accordingly when used in linearly arrangededge-gated molding applications in accordance with embodiments hereof,the slidable interface between melt inlets 241 a of nozzle seals 244 andmelt outlets 227 of diverter blocks 220 of injection manifold assembly702 permits thermal expansion of the injection manifold assembly withrespect to the nozzle seals in both longitudinal and transversedirections without damaging the nozzle seals or adversely affectingalignment between the nozzle seals and their respective mold cavities.

As in the previous embodiments, a plurality of wedge components 224 arecoupled to downstream surface 713 of injection manifold 760 in a similarmanner as shown and described with reference to the embodiment of FIG.2A, wherein each wedge component 224 may be used to apply a preload toan opposing pair of nozzle seals 244 that are associated therewith. Moreparticularly, the torqueing of screw 219 a within wedge component 224biases an opposing pair of diverter blocks 220 and associated nozzleseals 244 outward from a centerline C_(L) of the injection manifold 760toward their respective mold cavities (not shown) thereby applying apreload to each of the nozzle seals 244 that prevents leakage at theinterface between each diverter block 220 and injection manifold 760 andat the interface between each diverter block 220 and its associatednozzle seal 244 under operating conditions. This configuration alsoprovides access from the parting line P_(L) of the mold to the nozzleseals 244 for assembly and disassembly.

FIGS. 8 and 9 are perspective views of an injection manifold assembly802 in accordance with another embodiment hereof with FIGS. 8A, 8B and9A depicting various sectional views of injection manifold assembly 802taken along lines A-A and B-B of FIG. 8 and line A-A of FIG. 9,respectively. The embodiment of FIGS. 8 and 9 may be used with featuresdescribed with reference to other embodiments hereof and only featuresthat differ from those already described will be detailed herein.Injection manifold assembly 802 includes an injection manifold 860 thathas upstream surface 811, downstream surface 813, opposing side surfaces815, 815′ and opposing end surfaces 817, 817′. A keyed opening 890 isformed between opposing end surfaces 817, 817′ of injection manifold860. A substantially circular cross-sectioned portion 890 a of keyedopening 890 is spaced from upstream surface 811 of injection manifold860 along a centerline C_(L) thereof. A substantially trapezoidalcross-sectioned portion 890 b of keyed opening 890 extends from circularcross-sectioned portion 890 a through downstream surface 813 ofinjection manifold 860 to create a gap therein. Injection manifold 860also includes a series of slots 892, wherein each slot 892 extendsthrough an opposing side surface 815, 815′ to keyed opening 890. Slots892 help to define a row of finger portions 894 of injection manifold860 that define or otherwise align on each side of keyed opening 890. Asin the previous embodiments, a groove 801 is formed within upstreamsurface 811, downstream surface 813, and opposing side surfaces 815,815′ of injection manifold 860 for receiving a heating element 810 of aheater 872. Finger portions 894 are configured to flex outwardly asdiscussed in more detail below, and slots 892 thermally isolate fingerportions 894 from each other to avoid overheating under operatingconditions the finger portions 894 that are positioned inward of endsurfaces 817, 817′.

Injection manifold 860 includes a melt channel 832 formed therein forreceiving a melt stream of moldable material and distributing the meltstream via a series of melt channels 832′ to a plurality of melt outlets829. In this embodiment, each finger portion 894 of injection manifold860 includes a segment of a melt channel 832′ and a melt outlet 829,which is formed through a respective outward facing side surface 898thereof. Each melt outlet 829 is in fluid communication with arespective nozzle seal 244 that is in direct fluid communication with amold cavity during a molding cycle. As similarly described withreference to the embodiments above, each nozzle seal 244 has an upstreamend that is slidably disposed against planar side surface 898 thatsurrounds melt outlet 829 of finger portion 894 with a downstream end ofeach nozzle seal 244 being slidably receivable within a correspondingbore that surrounds a mold gate of the respective mold cavity associatedtherewith, as shown and described with reference to the embodiments ofFIGS. 2A and 6. Accordingly, nozzle seals 244 are otherwise not directlyattached or directly secured to injection manifold 860.

The engagement between primary seal surface 247 of gate seal 242 andsecond sealing surface 248 of cavity insert 104, as described above,assures axial alignment of nozzle tip 240 with a respective mold gate(not shown) in a cold condition, and together with the function of wedgecomponent 824 as described below maintains axial alignment of nozzle tip240 with its mold gate under operating conditions after thermalexpansion of injection manifold assembly 802. Conversely components 240,242 of nozzle seal 244 and injection manifold 860 may experience somemisalignment between melt outlets 829 of injection manifold 860 and meltinlets 241 a of nozzle tips 240 in a cold condition. However asinjection manifold assembly 802 is heated to an operating temperature,the upstream surfaces 241, 243 of nozzle tip 240 and gate seal 242,respectively, are slidable along planar side surface 898 of injectionmanifold 860 during thermal expansion of the components to substantiallyeliminate under operating conditions any misalignment between each meltoutlet 829 and its respective nozzle tip melt inlet 241 a. Accordinglywhen used in linearly arranged edge-gated molding applications inaccordance with embodiments hereof, the slidable interface between meltinlets of nozzle seals 244 and melt outlets of injection manifoldassembly 802 permits thermal expansion of the injection manifoldassembly with respect to the nozzle seals in both longitudinal andtransverse directions without damaging the nozzle seals or adverselyaffecting alignment between the nozzle seals and their respective moldcavities.

Injection manifold assembly 802 may be used with injection moldingapparatus 100, which is described with reference to FIG. 1, with someadaptation in place of injection manifold assembly 102. For such aninstallation, injection manifold 860 has a downstream connectorcomponent 386 of telescopic connector 380 threadably secured within anupstream end 803 thereof so as to be slidably connectable to upstreamconnector component 384 of telescopic connector 380, which is attachedto downstream end 338 of injection molding nozzle 108 as described withreference to FIGS. 1, 3 and 3A. With injection manifold assembly 802 soinstalled in injection molding apparatus 100, a melt inlet at upstreamend 803 of injection manifold 860 is positioned to receive a melt streamof moldable material from nozzle 108 and to fluidly communicate the meltstream to melt channels 832, 832′ and subsequently through melt outlets829 to nozzle seal 244.

Similar to the previous embodiments, a plurality of wedge components 824may be used to apply a preload to an opposing pair of nozzle seals 244that are associated therewith. Each wedge component 824 has atrapezoidal cross-section that is sized to be received withintrapezoidal cross-sectioned portion 890 b of keyed opening 890 and to besecured therein by a respective cap screw 819. Cap screws 819 arethreadably engageable within a corresponding threaded bore of a rod 896that is disposed to extend within circular cross-sectioned portion 890 aof keyed opening 890 between opposing ends 817, 817′ of injectionmanifold 860.

Wedge component 824 has opposing side contact surfaces 849 a, 849 b thatare angled toward each other in a similar manner as described above withreference to wedge component 224, with each injection manifold fingerportion 894 having a corresponding inside surface 815 b that is angledto abut against a respective side contact surface 849 a, 849 b of wedgecomponent 824. Accordingly, the torqueing of cap screw 819 within awedge component 824 will bias an opposing pair of injection manifoldfinger portions 894 and associated nozzle seals 244 outward from acenterline C_(L) of the injection manifold 860 toward their respectivemold cavities (not shown) thereby applying a preload to each of thenozzle seals 244 that prevents leakage at the interface between eachfinger portion 894 and its associated nozzle seal 244 under operatingconditions. This configuration permits an operator to apply any requiredpreload from the parting line P_(L) of the mold after assembly of theinjection molding apparatus.

FIGS. 10A and 10B are sectional views of an edge-gated injectionmanifold assembly 1002 in accordance with another embodiment hereof.FIGS. 10A and 10B depict injection manifold assembly 1002 fordistributing a melt stream of moldable material to a plurality of moldcavities aligned on opposing sides of the injection manifold assembly inaccordance with another embodiment hereof that may be used with allfeatures described with reference to other embodiments hereof such thatonly features that differ from those already described will be detailedherein. Injection manifold assembly 1002 includes injection manifold 260as described above.

Melt channel 332 of injection manifold 260 receives a melt stream ofmoldable material, as described above, and distributes the melt streamvia a plurality of melt outlets 229 to a plurality of diverter blocks1020, each of which directs the melt stream to a pair of opposing cavityinserts 104. Each diverter block 1020 includes a melt inlet 1023 and amelt outlet 1027 with a melt channel 1021 extending between each inletand outlet. Each diverter block 1020 is individually coupled to thedownstream surface of injection manifold 260 by cap screw 219, such thateach diverter block melt inlet 1023 is aligned with a respectiveinjection manifold melt outlet 229. Dowels (not shown) may also be usedbetween injection manifold 260 and diverter blocks 1020 to aid inaligning melt outlets 229 and with a corresponding melt inlet 1023during assembly as well as to maintain alignment therebetween duringthermal expansion that occurs as the system is brought to an operatingtemperature.

Outside surfaces 1015 a of each diverter block 1020, include arespective diverter block melt outlet 1027, are substantially flush withrespective opposing side surface 215, 215′ of injection manifold 260. Inthe embodiment shown in FIGS. 10A and 10B, each diverter block meltchannel 1021 includes a substantially 90° bend for directing the meltstream received through its respective diverter block melt inlet 1023 inan upstream surface thereof to its respective diverter block melt outlet1027 in side surface 1015 a thereof.

A series of biasing or cam components 1024 are coupled alongsubstantially a centerline C_(L) of the downstream surface of injectionmanifold 260 by respective cap screws 219 a, each of which passesthrough a central bore 1096 of a respective cam component 1024. Each camcomponent 1024 is disposed between a pair of diverter blocks 1020. Camcomponent 1024 has a flattened oval cross-section with opposing sidecontact surfaces 1049 a, 1049 b. Diverter blocks 1020 are cube shapedand include an inside surface 1015 b that abuts against a correspondingside contact surface 1049 a, 1049 b of a respective cam component 1024,when cam component 1024 is rotated to be in a locked position as shownin FIG. 10A. In the locked position of FIG. 10A, cam component 1024biases an opposing pair of diverter blocks 1020 and associated nozzleseals 244 outward from centerline C_(L) of injection manifold assembly1002 toward their respective mold cavities thereby applying a preload toeach of the nozzle seals 244 that prevents leakage at the interfacebetween each diverter block 1020 and its associated nozzle seal 244under operating conditions. Due to the shape of cam component 1024, camcomponents 1024 will remain in the locked position shown in FIG. 10Aeven if cap screw 219 a inadvertently comes loose during the injectionmolding process. In this embodiment, the preload that is applied bylocking cam component 1024 in place is a fixed preload that isdetermined by a distance between opposing side contact surfaces 1049 a,1049 b.

FIG. 10B shows cam component 1024 in an unlocked position with sidecontact surfaces 1049 a, 1049 b of cam component 1024 out of engagementwith the inside surfaces 1015 b of diverter blocks 1020 such that nobiasing force acts on diverter blocks 1020 and access to a respectivenozzle seal 244 may occur by simply removing a respective cap screw 219and the associated diverter block 1020. Once assembled or reassembled asshown in FIG. 10B, a tool may be used to engage apertures 1024 a, 1024 bof cam component 1024 to rotate the cam component into the lockedposition shown in FIG. 10A. Accordingly, this embodiment also permits anoperator to more conveniently apply the preload from the parting lineP_(L) of the mold after the remainder of injection molding apparatus 100is already assembled. In an embodiment, the injection molding system maybe brought to an operating temperature and thereafter a preload may beapplied, as discussed above, to prevent scoring that otherwise may haveoccurred if the preload were applied prior to heating-up the system.With this configuration nozzle seals 244, diverter blocks 1020, and camcomponents 1024 may be assembled and disassembled from a parting lineP_(L) of the mold.

Under operating conditions when injection manifold assembly 1002undergoes thermal expansion, a respective inside surfaces 1015 b of eachdiverter block 1020 will bear against a corresponding side contactsurface 1049 a, 1049 b of cam component 1024 to assure that thermalexpansion of diverter blocks 1020 occurs in the direction of theaforementioned interfaces. In embodiments hereof, accessibility of camcomponent 1024 from the parting line P_(L) of the mold permits a sealingforce between sealing interfaces of each diverter block to be adjustedfrom parting line P_(L) by utilizing a replacement cam component havinga greater or lesser width between side contact surfaces 1049 a and 1049b than cam component 1024 as the case may warrant and thereby prevent anexcessive load on the components of the system, for instance, if a lowpressure application is used or to assure an adequate preload, forinstance, if the preload provided by the original cam component 1024were found to be insufficient.

Nozzle seals 244 are positioned to receive the melt stream from arespective melt outlet 1027 of diverter block 1020 and direct the meltstream into a respective mold cavity in fluid communication therewith.An upstream surface 243 of gate seal 242 and an upstream surface 241 ofnozzle tip 240 are slidably disposed against a respective side surface1015 a of diverter block 1020, with each nozzle seal 244 otherwise notbeing directly attached or secured thereto. Accordingly, nozzle seal 244functions to accommodate thermal expansion of the components ofedge-gated injection manifold assembly 1002 as previously describedabove with reference to the previous embodiments.

Injection manifolds in accordance with embodiments hereof may be formedfrom H13. Diverter blocks in accordance with embodiments hereof may beformed from a thermally conductive material having sufficient strengthfor injection molding applications in which they are to be utilized,such as a high strength copper alloy or the like.

If a melt imbalance is discovered between melt cavities fed by aparticular injection manifold assembly according to an embodimenthereof, a melt imbalance between mold cavities may be addressed byselecting one or more diverter blocks (one or all of them) of differentmaterials. More particularly, as appropriate, one or more diverterblocks may be formed from a more thermally conductive material thanother of the diverter blocks in order to draw more heat from theinjection manifold and in turn to reduce the viscosity of the moldingmaterial flowing through that diverter block so as to promote increasedflow and therefore faster filling of its associated mold cavity.Conversely a less thermally conductive diverter block may be used inembodiments hereof to restrict heat transfer from the injection manifoldwhich would in turn increase the viscosity of the molding materialflowing through that diverter block so as to reduce flow and thereforeslow filling of its associated mold cavity. In this manner by selectinga diverter block with an appropriate thermal conductivity for each meltoutlet of an injection manifold, melt flow may be balanced between theassociated melt cavities for a particular injection manifold. Forinstance, at outlets positioned in a midsection of the injectionmanifold, which may be hotter, less thermally conductive diverter blocksmay be used, and at outlets near the ends of the injection manifold,which may be less hot, more thermally conductive diverter blocks may beused. In embodiments hereof, diverter blocks having different thermalconductivities may be of different high strength copper alloys, such asof Ampco 940 with a thermal conductivity of 208 w/mk and of Ampco 944with thermal conductivity of 156 w/mk. In another embodiment in order tobalance melt flow, each diverter block may be separately heated tocontrol the viscosity of the molding material flowing through thatblock.

In another embodiment in order to correct an imbalance between the moldcavities that are fed by a respective injection manifold assembly, meltchannels extending through the diverter blocks may be selected oraltered to have different widths and/or lengths there between to effecta respective melt flow rate and/or volume there through. For instance, awidth of a melt channel of a diverter block may be selected or madewider to promote increased melt flow through the respective diverterblock and therefore faster filling of the associated mold cavity, or maybe selected or made narrower to provide a more restricted flow throughthe respective diverter block and therefore slower filling of theassociated mold cavity.

In any of the embodiments described above, a copper plate may bedisposed across a top or upstream surface of the injection manifold toevenly distribute heat.

While various embodiments have been described above, it should beunderstood that they have been presented only as illustrations andexamples of the present invention, and not by way of limitation. It willbe apparent to persons skilled in the relevant art that various changesin form and detail can be made therein without departing from the spiritand scope of the invention. Thus, the breadth and scope of the presentinvention should not be limited by any of the above-described exemplaryembodiments, but should be defined only in accordance with the appendedclaims and their equivalents. It will also be understood that eachfeature of each embodiment discussed herein, and of each reference citedherein, can be used in combination with the features of any otherembodiment. All patents and publications discussed herein areincorporated by reference herein in their entirety.

What is claimed is:
 1. An edge-gated injection molding apparatuscomprising: an injection manifold assembly for distributing a meltstream of moldable material to a plurality of mold cavities that arearranged in a linear array on opposing sides of the injection manifoldassembly, the injection manifold assembly having a plurality of meltoutlets with each melt outlet being in fluid communication with arespective mold cavity of the plurality of mold cavities, and aplurality of biasing components secured to the injection manifoldassembly with each biasing component being disposed between a pair ofmelt outlets for biasing at least one of the pair of melt outletsoutward from a centerline of the injection manifold assembly toward itsrespective mold cavity; and a plurality of nozzle seals for receivingthe melt stream from the plurality of melt outlets of the injectionmanifold assembly and delivering the melt stream to the plurality ofmold cavities, wherein an upstream end of each nozzle seal is slidablydisposed against a respective melt outlet of the injection manifoldassembly such that the outward biasing of the melt outlet by itsrespective biasing component applies a preload to the nozzle seal. 2.The edge-gated injection molding apparatus of claim 1, wherein theinjection manifold assembly includes an injection manifold and aplurality of diverter blocks that are attached to a downstream surfaceof the injection manifold.
 3. The edge-gated injection molding apparatusof claim 2, wherein each of the plurality of diverter blocks defines oneof the plurality of melt outlets of the injection manifold assemblyagainst which a respective nozzle seal is slidably disposed and includesa surface that contacts a corresponding surface of the biasing componentassociated with the melt outlet.
 4. The edge-gated injection moldingapparatus of claim 2, wherein the injection manifold includes a meltinlet in an upstream surface that is in fluid communication with a meltchannel formed therein for receiving the melt stream of moldablematerial and distributing the melt stream via a plurality of meltoutlets in the downstream surface thereof to the plurality of diverterblocks attached thereto.
 5. The edge-gated injection molding apparatusof claim 4, wherein each diverter block includes a melt inlet and a meltoutlet with a melt channel extending there between with the melt outletof each diverter block being in an exterior side surface thereof anddefining one of the plurality of melt outlets of the injection manifoldassembly against which a respective nozzle seal is slidably disposed. 6.The edge-gated injection molding apparatus of claim 5, wherein the meltchannel of each diverter block includes a bend for directing the meltstream received through the melt inlet in an upstream surface thereof tothe melt outlet in the exterior side surface thereof.
 7. The edge-gatedinjection molding apparatus of claim 5, wherein each diverter blockincludes an interior side surface that contacts a corresponding contactsurface of the biasing component associated with the melt outlet definedby the diverter block.
 8. The edge-gated injection molding apparatus ofclaim 7, wherein the biasing component is a wedge component and theinterior side surface of the diverter block is angled to abut againstthe corresponding contact surface of the wedge component.
 9. Theedge-gated injection molding apparatus of claim 7, wherein the biasingcomponent is a rotatable cam component having a locked position in whicha contact surface of the cam component abuts against the interior sidesurface of the diverter block.
 10. The edge-gated injection moldingapparatus of claim 2, wherein each diverter block is individuallyattached to the downstream surface of the injection manifold to bepositioned such that a melt inlet of the diverter block is aligned witha respective melt outlet in the bottom surface of the injection manifoldand a melt outlet in an exterior side surface of the diverter blockdefines one of the plurality of melt outlets of the injection manifoldassembly against which a respective nozzle seal is slidably disposed.11. The edge-gated injection molding apparatus of claim 10, wherein theexterior side surface of each diverter block that includes the meltoutlet is parallel with a respective side surface of the injectionmanifold.
 12. The edge-gated injection molding apparatus of claim 10,wherein the exterior side surface of each diverter block that includesthe melt outlet is at an acute angle relative to a centerline of theinjection manifold assembly such that the exterior side surface of eachdiverter block is angled relative to a respective side surface of theinjection manifold.
 13. The edge-gated injection molding apparatus ofclaim 10, wherein the injection manifold is T-shaped.
 14. The edge-gatedinjection molding apparatus of claim 1, wherein the injection manifoldassembly includes an injection manifold having a keyed opening and aplurality slots that define two rows of finger portions and wherein eachfinger portion includes one of the plurality of melt outlets of theinjection manifold assembly.
 15. The edge-gated injection moldingapparatus of claim 14, wherein the plurality of biasing components are aplurality of wedge components with each wedge component being disposedwithin a portion of the keyed opening between the rows of fingerportions to contact a pair of finger portions.
 16. The edge-gatedinjection molding apparatus of claim 15, wherein each wedge componenthas opposing side contact surfaces that are angled toward each otherwith each injection manifold finger portion having a correspondinginterior surface that is angled to abut against a respective sidecontact surface of the wedge component.
 17. The edge-gated injectionmolding apparatus of claim 14, wherein each wedge component has atrapezoidal cross-section that is sized to be received within acorrespondingly shaped portion of the keyed opening to be securedtherein.
 18. The edge-gated injection molding apparatus of claim 14,wherein the injection manifold includes a melt channel with each fingerportion including a segment of the melt channel formed therein forreceiving the melt stream and distributing the melt stream to the meltoutlet thereof.
 19. The edge-gated injection molding apparatus of claim18, wherein each of the melt outlets is formed through a respectiveoutward facing side surface of the finger portion.
 20. The edge-gatedinjection molding apparatus of claim 1, wherein a downstream end of eachnozzle seal is received within a bore that surrounds a mold gate of therespective mold cavity associated therewith.